Hello excellent friends

Eric Wong normalperson at yhbt.net
Tue Aug 31 02:17:08 EDT 2010

Curtis <curtis.schofield at gmail.com> wrote:
> I have read your tun in article and I have tried to make sysctl
> changes - the benchmarks are not very significant. I love how well the
> signals are laid out and how excellently unicorn responds to them - I
> am hoping to get back to mongrel like performance . We were using
> nginx to haproxy to 32 mongrels
> No I have set up a unix domain socket with 2mb send and receive buffer
> and a backlog of 2048 - I didn't see a change with the send receive
> buffer tuning and I have yet to try a smaller backlog to see. If that
> helps. Any info?

Hi, I'm not sure what size of requests and responses you get, but 2mb
seems like a lot, especially for requests (unless you handle a lot of
big uploads).

Even with large requests/responses, huge buffers means more pressure on
the kernel allocator and you're also hurting CPU cache locality.  So
larger buffers can hurt performance as well as help, I'll make a note of
that in the documentation.

The backlog shouldn't change performance much.  A larger one can let you
withstand short traffic bursts and increase reliability while

> I am tuning for osx in dev and centos5 in production. Thank you for
> your great work cleaning mongrel into a first class unix friend.

You're welcome!

Eric Wong

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